原子吸收分光光度法快速测定铬铁矿中钙、镁、锰   总被引：2，自引：0，他引：2  

熊艳 《安徽地质》2006,16(4):270-272

通过在标液中加入相应的Sr来消除离子干扰,采用原子吸收分光光度法快速测定CaO、MgO、MnO的含量,方法经国家标准物质验证,其RSD<2%(n=6)。其结果与标准值相符。方法达到了准确、简便、快速、实用性强。  相似文献   

Preparation of Nano‐Lepidocrocite and an Investigation of Its Ability to Remove a Metal Complex Dye     

Mohsen Sheydaei  Soheil Aber 《洁净——土壤、空气、水》2013,41(9):890-898

Lepidocrocite (γ‐FeOOH) nanoparticles were synthesized from iron(II) sulfate solution and characterized using X‐ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform‐IR (FT‐IR), nitrogen adsorption, and point of zero charge pH (pH_PZC) analyses. TEM, XRD, and FT‐IR analyses proved the synthesis of nano‐lepidocrocite. Surface area and pH_PZC of the synthesized lepidocrocite were 68.1 m² g^?1 and 4.8, respectively. Utilization of the synthesized lepidocrocite in the adsorption of Lanacron brown S‐GL (LBS‐GL) from aqueous solutions was investigated, and the effect of lepidocrocite dosage, pH, temperature, and contact time on this process were optimized and modeled using response surface methodology approach. The lepidocrocite dosage of 0.015 g, pH 3.5, temperature of 38°C, and contact time of 100 min were determined as optimum adsorption conditions. Isotherm and kinetics of the adsorption process were analyzed at the optimum conditions. The equilibrium data were fitted well to the Langmuir isotherm model. The maximum monolayer adsorption capacity was 528.21 mg g^?1. The adsorption process was described by the pseudo‐second‐order kinetic model. Furthermore, the effect of pH on the desorption of LBS‐GL was investigated. High LBS‐GL desorption efficiency was achieved at a high pH value.  相似文献   

铵锌镉还原法测试硝酸盐氮、氧同位素方法研究          下载免费PDF全文

尹希杰  杨海丽  郭浩然  陈淳青  崔坤磊 《应用海洋学学报》2021,40(4):721-727

本研究利用铵锌镉还原法将海水、湖水和自来水水体中硝酸盐转化为N₂O气体测试氮、氧同位素, 结果表明当反应体系的pH值在6～8之间, NO₃^-还原为NO₂^-的转化率大于95%, NO₂^-还原为N₂O的转化率大于99%。配置5种丰度的硝酸盐氮、氧同位素标样, 将实验结果与理论值绘制校准曲线, 氮同位素校准曲线斜率为0.48, 相关性良好(R²=0.999 8), 5种丰度δ¹⁵N_N2O标准偏差在0.18‰～0.43‰之间(n=5);氧同位素校准曲线斜率为0.70, 相关性良好(R²=0.999 6), 5种丰度δ¹⁸O_N2O标准偏差在0.27‰～0.46‰之间(n=5)。铵锌镉还原法与镉柱还原法测定硝酸盐氮、氧同位素结果的精密度和准确度一致, 同时海水、湖水和自来水3种不同类型水样的硝酸盐氮、氧同位素测试数据满足实验要求, 而且在实验流程的简洁性和高效性方面更具优势。  相似文献   

纳米TiO2分离富集ICP-MS法测定河口环境样品中重金属研究     

黄霄红  卢豪良 《亚热带资源与环境学报》2013,(2):35-40

建立了以纳米二氧化钛（TiO2）作为吸附剂填充微柱,电感耦合等离子体质谱（ICP-MS）法测试Cu^2＋,Cd^2＋,Pb^2＋和Ni^2＋离子的分析方法．考察了不同pH值、洗脱液浓度、样品流速、体积和外源干扰离子的影响,实验结果表明在pH值8～10范围内待测离子可被TiO2定量吸附,2．0molL^-1HNO3可将吸附在微柱上的待测物完全洗脱,优化条件下本方法对溶液中Cu^2＋,Cd^2＋,Ph^2＋和M^2＋离子检出限分别为：0．02,0．01,0．01,0．02μgL～,相对标准偏差小于2％（n=7）,富集系数50倍．对水系沉积物标准物质（GBW07310）的测定值与标准值相一致,方法具有简便、快速,灵敏度高,重现性好的优点,可满足河口水体与沉积物样品中痕量金属元素定量分析的要求．  相似文献   

水声学方法对黄河口水下底坡失稳现象研究     

阎通  李萍  杨作升  庞重光 《中国海洋大学学报(自然科学版)》1999,(2)

对黄河三角洲东北部地区的高分辨率水声学资料进行了综合研究。根据所记录的破坏土体变形程度、运动产生的平面形状和地貌特征形态,对土体失稳过程进行分类：浅表土体变形、塌陷凹坑、滑坡和沉积物重力流。结果表明：（１）浅表土体形变的变形程度最低,出现在研究区斜坡上部平滑海底,主要为绳网状泄水构造和表层拉张裂隙。（２）塌陷凹坑在研究区内广泛出现,是局部土体液化后发生了垂直沉降的结果。（３）滑坡多发生在水下斜坡的中上部,由弧形塌陷区、狭窄的冲沟通道和负地形沉积物堆积区组成。滑坡陡坎后缘发现拉张裂隙。（４）沉积物重力流是土体发生变形程度最大,搬运距离最长的土体破坏变形形式。局部区域多次受到沉积物重力流切割和充填作用。  相似文献   

Spatial heterogeneity of soil mineral oxide components in depression between karst hills,Southwest China   总被引：3，自引：0，他引：3  

Hu Du  Kelin Wang  Wanxia Peng  Fuping Zeng  Tongqing Song  Hao Zhang  Shiyang Lu 《中国地理科学(英文版)》2014,24(2):163-179

In karst regions,the spatial heterogeneity of soil mineral oxides and environmental variables is still not clear.We investigated the spatial heterogeneity of SiO2,Al2O3,Fe2O3,CaO,MgO,P2O5,K2O,and MnO contents in the soils of slope land,plantation forest,secondary forest,and primary forest,as well as their relationships with environmental variables in a karst region of Southwest China.Geostatistics,principal component analysis(PCA),and canonical correlation analysis(CCA)were applied to analyze the field data.The results show that SiO2was the predominant mineral in the soils(45.02%–67.33%),followed by Al2O3and Fe2O3.Most soil mineral oxide components had a strong spatial dependence,except for CaO,MgO,and P2O5in the plantation forest,MgO and P2O5in the secondary forest,and CaO in the slope land.Dimensionality reduction in PCA was not appropriate due to the strong spatial heterogeneity in the ecosystems.Soil mineral oxide components,the main factors in all ecosystems,had greater influences on vegetation than those of conventional soil properties.There were close relationships between soil mineral oxide components and vegetation,topography,and conventional soil properties.Mineral oxide components affected species diversity,organic matter and nitrogen levels.  相似文献   

A role for nitrite in the production of nitrous oxide in the lower euphotic zone of the oligotrophic North Pacific Ocean     

《Deep Sea Research Part I: Oceanographic Research Papers》2014

Understanding the role of the oceans in the Earth's changing climate requires comprehension of the relevant metabolic pathways which produce climatically important trace gases. The global ocean represents one of the largest natural sources of nitrous oxide (N₂O) that is produced by selected archaea and/or bacteria during nitrogen (N) metabolism. In this study, the role of nitrite (NO₂⁻) in the production of N₂O in the upper water column of the oligotrophic North Pacific Subtropical Gyre was investigated, focusing primarily on the lower euphotic zone where NO₂⁻ concentrations at the primary NO₂⁻ maximum reached 195 nmol L⁻¹. Free-drifting sediment trap arrays were deployed to measure N cycle processes in sinking particulate material and the addition of selected N substrates to unpreserved sediment traps provided an experimental framework to test hypotheses regarding N₂O production pathways and controls. Sinking particles collected using NO₂⁻-amended, unpreserved sediment traps exhibited significant production of N₂O at depths between 100 and 200 m. Subsequent stable isotope tracer measurements conducted on sediment trap material amended with ¹⁵NO₂⁻ yielded elevated δ¹⁵N values of N₂O, supporting N₂O production via a NO₂⁻ metabolism pathway. Experiments on seawater collected from 150 m showed N₂O production via NO₂⁻ metabolism also occurs in the water-column and indicated that the concentration of NO₂⁻ relative to NH₄⁺ availability may be an important control. These findings provide evidence for the production of N₂O via nitrifer-denitrification in the lower euphotic zone of the open ocean, whereby NO₂⁻ is reduced to N₂O by ammonia-oxidizing microorganisms.  相似文献   

漂浮通量箱法和扩散模型法测定内陆水体CH_4和N_2O排放通量的初步比较研究   总被引：1，自引：0，他引：1       下载免费PDF全文

高洁  郑循华  王睿  廖婷婷  邹建文 《气候与环境研究》2014,19(3):290-302

采用漂浮通量箱法和扩散模型法同步地观测了模拟内陆水体在不同条件下的CH4和N2O的水-气交换通量,旨在比较两类方法取得结果的异同。结果显示:这两类方法所测得的绝大多数CH4排放通量都与水中溶解氧呈显著线性负相关(显著性系数P0.001)。同时N2O排放通量与表层水温及水中铵态氮、硝态氮、溶解碳和溶解氧的关系可用包含所有上述水环境因素的Arrhenius动力学方程来表达,这些因素可以共同解释86%~90%的N2O通量变化(P0.0001),且不同方法测定的N2O通量的表观活化能和对表层水温的敏感系数分别介于47~59 kJ mol-1和1.92~2.27之间;扩散模型法所获得的CH4和N2O通量分别是箱法测定值的13%~175%和15%~240%,差异程度因模型而异;不同模型取得通量间相差20%~1200%,平均相差2.3倍。上述结果表明:仅用一种模型方法来取得CH4或N2O排放通量易形成较大偏差;不同扩散模型法和箱法测定的通量在反映CH4和N2O排放的内在规律方面具有一致性,但它们对真实气体通量的测量是否都存在不同程度的系统误差,尚需进一步研究。  相似文献   

Petrogenesis of the Piqiang mafic-ultramafic layered intrusion and associated Fe-Ti-V oxide deposit in Tarim Large Igneous Province,NW China     

《International Geology Review》2012,54(18):2249-2275

ABSTRACT

The Piqiang intrusion is one of the two important ma?c-ultrama?c layered intrusions that host giant Fe-Ti-V oxide deposits in the Permian Tarim Large Igneous Province, NW China. The intrusion mainly consists of gabbro, anorthosite and minor plagioclase-bearing clinopyroxenite in the marginal zone. Disseminated to massive Fe-Ti oxide ores occur as layers and lenses within the gabbro. SHRIMP zircon U-Pb results from both a gabbro from the Piqiang intrusion and a granite from the surrounding granitic dyke yield ages of ~270 Ma. Geochemically, the Piqiang silicate rocks are enriched in light rare earth elements (LREE) and large ion lithophile elements (LILE), moderately depleted in high ?eld strength elements (HFSE), and have a limited range of Sr-Nd-Hf isotopic compositions. The similar mineralogy, mineral compositions, and trace element characteristics of the layered units suggest that all the rocks are co-magmatic. The parental magma is Fe-Ti-rich and is akin to the most primitive diabasic dyke which is associated with the Piqiang intrusion. Partial melting of the Tarim mantle plume with involvement of a subduction-metasomatized lithospheric mantle source best explains the geochemistry and petrogenesis of the parental magmas of the Piqiang intrusion. We propose that the lithospheric mantle source may have been metasomatized by subduction-related materials and the metasomatic enrichment of this source region which may be correlated with oceanic sediment recycling during southward subduction of the South Tianshan oceanic slab during the Early-Middle Paleozoic. Crystal settling and mechanical sorting is the predominant process responsible for the formation of the massive Fe-Ti oxide ores in the Piqiang intrusion. Central to ore formation is a combination of the protracted differentiation history of a Fe-Ti-enriched parental magma and the later addition of external H₂O from the country rocks to the slowly cooling magma chamber.  相似文献   

氧化铬对铝型材厂碱蚀渣制备铝方柱石材料结构的影响     

罗旭东  曲殿利  张国栋  刘海啸  吕楠 《矿物学报》2012,32(1):146-150

利用铝型材厂碱蚀渣为主要原料,采用二步煅烧工艺制备铝方柱石材料。探索二次煅烧温度对铝型材厂碱蚀渣制备铝方柱石材料相组成、结晶度、微观结构的影响,进而研究氧化铬对铝方柱石材料相组成、微观结构的影响。采用同步热分析、X射线衍射、扫描电镜及相关分析软件表征制备的铝方柱石材料的相组成和显微结构。结果表明：铝型材厂碱蚀渣中有大量可烧失成分,物料需要进行致密化处理,再经过1500℃煅烧后的铝方柱石材料结构中具有明显的铝方柱石条柱状结构,结晶度增大,铝方柱石相对含量达到91%。随着氧化铬加入量增加,结构中的铝铬酸钙相增加。当氧化铬加入量为2%时,试样中结晶相的结晶度最高,形成条柱状铝方柱石相与立方状铝铬酸钙相共存的结构。当氧化铬加入量4%时,试样中铝方柱石相几乎消失,结晶度降低。  相似文献